Previous research has shown that children of depressed mothers are at heightened risk for a variety of behavioral and emotional disturbances. In this longitudinal study of 144 mother-child pairs, the impact of maternal depression on children's psycho-biological and behavioral development is being explored. At the first assessment point, when the children were 14 months of age, it was found that infants of depressed mothers exhibit atypical patterns of frontal electro-encephalographic (EEG) activity, characterized by reduced left frontal activation. It is hypothesized that reduced left frontal activation reflects an increased vulnerability to experience negative affect, a vulnerability that may play a role in the etiology of depression and other mental disorders. When assessments of children's brain activity and behavior were conducted at 39 months of age, it was found that children whose mothers remained depressed across the two time points showed stable patterns of reduced left frontal brain activity. Furthermore, children reported to have behavior problems at 39 months of age were more likely to have atypical front EEG patterns than those without behavior problems. The aim of the proposed research is to assess the children and their mothers at a third time point, when the children turn 6 years of age. This phase of the longitudinal study will allow us to evaluate the clinical significance of early measures of brain activity for predicting later psychological adjustment of school-aged children who are at risk for emotional and behavioral problems. The specific aims are: 1. to examine the cumulative effects of maternal depression on children's development, as reflected in both behavioral and psychobiological measures. Behavioral measures are designed to assess children's mental health, competence and adaptive functioning, and social relationships. Psychobiological measures consist of frontal EEG patterns, autonomic activity (heart rate and vagal tone), salivary cortisol, and sleep patterns. 2. To determine, in this sample of children who are at risk for behavioral and emotional disturbances, the extent to which psychobiological measures are predictive of children's emotional and behavioral disturbances when they reach early elementary school age.